This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-079388, filed Mar. 19, 2001; and No. 2001-140313, filed May 10, 2001, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a silver halide color photographic material, specifically, a color reversal material excellent in the color saturation, the faithfulness of intermediate color, and description.
Further, the present invention relates to a method of forming a color reversal image using the above-mentioned silver halide color photographic material.
2. Description of the Related Art
In the color photographic material, if the improvement of saturation is limited only to primary colors, it can be realized by lessening the overlap in the spectral sensitivity distribution of blue-, green- and red-lightsensitive emulsion layers, but in this case, the faithfulness of intermediate color is deteriorated (for example, Satoru Honjou, xe2x80x9cCharacteristic and Technique of Color Reversal Filmxe2x80x9d Journal of Japan Photography Academy Vol.48, p.274 (1985)). It is disclosed in Jpn. Pat. Appln. KOKAI Publication No. (hereinafter, referred to as JP-A-) 2-272450, JP-A""s-2-272540 and 3-122636 that a color photographic material having a silver halide emulsion layer from which a development-inhibiting agent is released in black and white development and substantially no contribution is provided to the formation of color dye, is effective in order to improve the color saturation of a color reversal photographic material and the faithfulness of hue including an intermediate color. However, according to these techniques, although the improvement in the saturation of primary colors and the discrimination in the region of from blue to green are superior, there is a problem in the faithfulness of the intermediate colors, therefore it is necessary to solve the problem.
As a technique for improving the color fidelity, as described in the specifications of U.S. Pat. Nos. 4,663,271, 4,705,744 and 4,707,436, JP-A""s-62-160448 and 63-89850, there is disclosed an invention in which an inter image effect-donating layer having a different spectral sensitivity distribution from that of blue-, green- and red-main lightsensitive layers is arranged. However, there is hardly found a specific description of actually realizing this in the system of a color reversal photographic material. Even if the color reversal material is actually manufactured by such configuration, the inter-image effect from a donor layer is not sufficiently expressed, the color-mixing from a layer provided in the vicinity of the donating layer is enhanced, and it was found out that the color of a photographed body cannot be adequately and faithfully reproduced.
Further, in JP-A""s-2-272450, 3-122636 and 8-328212, those concerning a method of providing the inter image effect-donating layer and a method of setting spectral sensitivity in the silver halide color photographic material are disclosed. However, since the inter-image effect from a donor layer is not adequately expressed even by these configurations and a color-sensitive color layer provided in the vicinity of the donor layer generates an unnecessary color and color opaque by an emulsion which the donor layer contains, it was grasped that the color of a photographed body cannot be adequately and faithfully reproduced.
JP-A""s-4-039653 and 4-039654 disclose techniques concerning the gradation design of a color reversal film for improving the flesh color fidelity. However, these techniques designed to optimized the flesh color reproduction by xe2x80x9clowering the inclination in D-log E curve of magenta in comparison with that of yellowxe2x80x9d, and bring about serious defect that a gray color changes depending on its concentration. The term xe2x80x9cflesh colorxe2x80x9d herein means the light-skin of Macbeth color chart No.2. xe2x80x9cThese publications are silent about any method of technically improving the defect. Further, these are techniques for stabilizing the tint change of flesh colors having different concentrations, and nothing is taken into consideration concerning the improvement in the faithfulness of various intermediate colors.
Therefore, in the color reproduction of a color reversal photographic material, development in a technique by which both saturation and faithfulness are compatible, is desired.
It is an object of the present invention to provide a silver halide color photographic material, specifically, a color reversal material in which the saturation of color reproduction and the hue faithfulness of intermediate color are improved.
Further, it is also an object of the present invention to provide a method of forming a color reversal image using the above-mentioned silver halide color photographic material.
The inventors have conducted extensive and intensive studies, and as a result, the objects of the present invention have been attained by the procedures below.
(1) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a maximum absorption wavelength of the green-sensitive emulsion layer represented by xcexmax(G) being in the range of 500 nmxe2x89xa6xcexmax(G)xe2x89xa6570 nm, and
the photographic material further having at least one short-wavelength-green-sensitive emulsion layer (CL layer) meeting the following requirements (i) and (ii):
(i) a maximum absorption wavelength of the CL layer represented by xcexmax(C) being in the range of 490 nmxe2x89xa6xcexmax(C)xe2x89xa6560 nm, and 80 nmxe2x89xa7xcexmax(G)xe2x88x92xcexmax(C)xe2x89xa75 nm, and
(ii) the total iodine amount of silver halide grains contained in the CL layer being in the range from 60% to 300% of that contained in the green-sensitive emulsion layer
(2) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a weight-averaged wavelength of spectral sensitivity distribution of the green-sensitive emulsion layer represented by xcexG being in the range of 500 nmxe2x89xa6xcexGxe2x89xa6570 nm, and
the photographic material further having at least one short-wavelength-green-sensitive emulsion layer (CL layer) meeting the following requirements (iii) and (iv):
(iii) a weight-averaged wavelength of spectral sensitivity distribution of the CL emulsion layer represented by xcexC being in the range of 490 nmxe2x89xa6xcexCxe2x89xa6560 nm, and 80 nmxe2x89xa7xcexGxe2x88x92xcexCxe2x89xa75 nm, and
(iv) the total iodine amount of silver halide grains contained in the CL layer being in the range from 60% to 300% of that contained in the green-sensitive emulsion layer
(3) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a maximum absorption wavelength of the blue-sensitive emulsion layer represented by xcexmax(B) being in the range of 440 nmxe2x89xa6xcexmax(B)xe2x89xa6500 nm, and
the photographic material further having at least one short-wavelength-blue-sensitive emulsion layer (VL layer) meeting the following requirements (v) and (vi):
(v) a maximum absorption wavelength of the VL layer represented by xcexmax(V) being in the range of 400 nmxe2x89xa6xcexmax(V)xe2x89xa6460 nm, and 100 nmxe2x89xa7xcexmax(B)xe2x88x92xcex2max(V)xe2x89xa75 nm, and
(vi) the total iodine amount of silver halide grains contained in the VL layer being in the range from 40% to 250% of that contained in the blue-sensitive emulsion layer
(4) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a weight-averaged wavelength of spectral sensitivity distribution of the blue-sensitive emulsion layer represented by xcexB being in the range of 440 nmxe2x89xa6xcexBxe2x89xa6500 nm, and
the photographic material further having at least one short-wavelength-blue-sensitive emulsion layer (VL layer) meeting the following requirements (vii) and (viii):
(vii) a weight-averaged wavelength of spectral sensitivity distribution of the VL layer represented by xcexV being in the range of 400 nmxe2x89xa6xcexVxe2x89xa6460 nm, and 100 nmxe2x89xa7xcexBxe2x88x92xcexVxe2x89xa75 nm, and
(viii) the total iodine amount of silver halide grains contained in the VL layer being in the range from 40% to 250% of that contained in the blue-sensitive emulsion layer
(5) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a maximum absorption wavelength of the green-sensitive emulsion layer represented by xcexmax(G) being in the range of 500 nmxe2x89xa6xcexmax(G)xe2x89xa6570 nm,
a maximum absorption wavelength of the blue-sensitive emulsion layer represented by xcexmax(B) being in the range of 440 nmxe2x89xa6xcexmax(B)xe2x89xa6500 nm, and
the photographic material further having at least one short-wavelength-green-sensitive emulsion layer (CL layer) and at least one short-wavelength-blue-sensitive emulsion layer (VL layer) each meeting the following requirements (ix) and (x):
(ix) a maximum absorption wavelength of the CL layer represented by xcexmax(C) being in the range of 490 nmxe2x89xa6xcexmax(C)xe2x89xa6560 nm, and 80 nmxe2x89xa7xcexmax(G)xe2x88x92xcexmax(C)xe2x89xa75 nm, and
(x) a maximum absorption wavelength of the VL layer represented by xcexmax(V) being in the range of 400 nmxe2x89xa6xcexmax(V)xe2x89xa6460 nm, and 100 nmxe2x89xa7xcexmax(B)xe2x88x92xcexmax(V)xe2x89xa75 nm
(6) A silver halide color photographic material comprising at least one blue-sensitive emulsion layer (BL layer), at least one green-sensitive emulsion layer (GL layer) and at least one red-sensitive emulsion layer (RL layer) on a support, wherein,
a weight-averaged wavelength of spectral sensitivity distribution of the green-sensitive emulsion layer represented by xcexG being in the range of 500 nmxe2x89xa6xcexGxe2x89xa6570 nm,
a weight-averaged wavelength of spectral sensitivity distribution of the blue-sensitive emulsion layer represented by xcexB being in the range of 440 nmxe2x89xa6xcexBxe2x89xa6500 nm, and
the photographic material further having at least one short-wavelength-green-sensitive emulsion layer (CL layer) and at least one short-wavelength-blue-sensitive emulsion layer (VL layer) each meeting the following requirements (xi) and (xii):
(xi) a weight-averaged wavelength of spectral sensitivity distribution of the CL layer represented by xcexC being in the range of 490 nmxe2x89xa6xcexCxe2x89xa6560 nm, and 80 nmxe2x89xa7xcexGxe2x88x92xcexCxe2x89xa75 nm, and
(xii) a weight-averaged wavelength of spectral sensitivity distribution of the VL layer represented by xcexV being in the range of 400 nmxe2x89xa6xcexVxe2x89xa6460 nm, and 100 nmxe2x89xa7xcexBxe2x88x92xcexVxe2x89xa75 nm
(7) The silver halide color photographic material described in any one of (1) to (6) above, wherein image dye is not substantially formed in the CL layer and/or the VL layer.
(8) The silver halide color photographic material described in any one of (1), (2), (5), (6) and (7) above, wherein a non-lightsensitive layer having a color mixing prevention ability, being provided between the CL layer and a lightsensitive emulsion layer other than the CL layer.
(9) A method of forming a color reversal image comprising black and white developing any one of the silver halide color photographic materials described in (1) to (8) above, followed by color developing the same.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
xe2x80x9cThe maximum absorption wavelength of the lightsensitive emulsion layer represented by xcexmax(n)xe2x80x9d mentioned in the present invention, wherein n represents a sensitive color of the emulsion layer and is selected from the characters of V, B, C, G and R, is a wavelength at which the absorption ratio of said emulsion layer becomes a maximum value. The wavelength of xcexmax(n) is within the wavelength region of 350 nm or more and 700 nm or less. Each of the wavelength xcexmax(n) may be obtained by pealing the emulsion layer from the coated material and measuring its absorption property.
xe2x80x9cThe weight-averaged wavelength of spectral sensitivity distribution of a lightsensitive emulsion layer represented by xcexnxe2x80x9d mentioned in the present invention, wherein n represents a sensitive color of the emulsion layer and is selected from the characters of V, B, C, G and R, is defined in the following       λ    ⁢          xe2x80x83        ⁢    n    =            ∫      350      700        ⁢                  λ        ·        S            ⁢              xe2x80x83            ⁢              n        ⁢                  (          λ          )                    ⁢              xe2x80x83            ⁢                        ⅆ          λ                /                              ∫            350            700                    ⁢                      S            ⁢                          xe2x80x83                        ⁢                          n              ⁢                              (                λ                )                                      ⁢                          xe2x80x83                        ⁢                          ⅆ              λ                                          
wherein Sn (xcex) is the spectral distribution of the sensitivity giving a color density in an amount of 0.5 times the full color density of each of the lightsensitive emulsion layers, wherein n represent a color to which an emulsion layer is sensitive and is selected from the characters of V, B, C, G and R. Provided that when the lightsensitive emulsion layer does not form a color dye, Sn (xcex) is defined as the spectral distribution of the sensitivity giving a blackened silver density in an amount of 0.2 times the maximum blackened silver density obtained by white light exposure when a sample of a single-layered photographic material in which only the emulsion layer is coated on a support, is silver-developed.
In the invention, the color density of each color-sensitive layer is defined as that obtained by processing a photographic material with the same processing as that described later in the section of Examples of the specification. Provided that when a lightsensitive emulsion layer does not form a color dye, and thus it is to be silver-developed, the density is defined as that obtained by processing a photographic material with the same processing as that described later in the section of Examples of the specification, except that the reversal, color development, pre-bleaching, and bleaching steps are omitted.
In order to enhance saturation without deterioration in color fidelity, it is important to balance among the spectral sensitivity distribution of the emulsion layers. Especially, since distinction between similar colors largely affects the color fidelity and saturation, it is important to control the spectral sensitivity distribution between the green-sensitive emulsion layer and the short-wavelength-green-sensitive emulsion layer and between the blue-sensitive emulsion layer and the short-wavelength-blue sensitive emulsion layer.
xcexC of the short-wavelength-green-sensitive emulsion layer (CL layer) is 490 nmxe2x89xa6xcexCxe2x89xa6560 nm, and the CL layer exhibits an orange color, and is required to be a layer sensitive to cyan light. xcexC is preferably 510 nmxe2x89xa6xcexCxe2x89xa6540 nm, and more preferably 520 nmxe2x89xa6xcexCxe2x89xa6535 nm.
In order to realize such an absorption wavelength of the CL layer, it is preferable to add a quinoline type spectral sensitizing dye that is described in JP-A-5-341429 to the silver halide emulsion that is contained in said layer.
Further, xcexG of the green-sensitive emulsion layer (GL layer) is required to be 500 nmxe2x89xa6xcexGxe2x89xa6570 nm, and the GL layer exhibits a magenta color, and is a layer sensitive to green light. xcexG is preferably 535 nmxe2x89xa6xcexGxe2x89xa6560 nm, and more preferably 545 nmxe2x89xa6xcexGxe2x89xa6555 nm.
The relation between the above-mentioned xcexG and xcexC is required to be 80 nmxe2x89xa7xcexGxe2x88x92xcexCxe2x89xa75 nm, preferably 60 nmxe2x89xa7xcexGxe2x88x92xcexxe2x89xa710 nm, and the more preferable relation is 40 nmxe2x89xa7xcexGxe2x88x92xcexCxe2x89xa715 nm.
xcexV of the short-wavelength-length-blue-sensitive emulsion layer (VL layer) is required to be 400 nmxe2x89xa6xcexVxe2x89xa6460 nm. xcexV is preferably 410 nmxe2x89xa6xcexVxe2x89xa6450 nm, and more preferably 420 nmxe2x89xa6xcexVxe2x89xa6440 nm.
Further, xcexB of the blue-sensitive emulsion layer (BL layer) is required to be 440 nmxe2x89xa6xcexBxe2x89xa6500 nm, preferably 450 nmxe2x89xa6xcexBxe2x89xa6490 nm, and more preferably 460 nmxe2x89xa6xcexBxe2x89xa6480 nm.
The relation between the above-mentioned xcexB and xcexV is required to be 100 nmxe2x89xa7xcexBxe2x88x92xcexVxe2x89xa75 nm, preferably 75 nmxe2x89xa7xcexBxe2x88x92xcexxe2x89xa710 nm, and the more preferable relation is 50 nmxe2x89xa7xcexBxe2x88x92xcexVxe2x89xa715 nm.
In many cases, since a maximum absorption wavelength xcexmax(n) of an emulsion layer originates in the absorption of J aggregate of the spectral sensitizing dye in the emulsion, xcexmax(n) coincides with the weight-averaged wavelength of spectral sensitivity distribution represented by xcexn. However, depending on the adsorption state and quantum efficiency of the spectral sensitizing dye, the maximum absorption wavelength of an emulsion sometimes does not correspond to the weight-averaged wavelength of spectral sensitivity distribution of the emulsion. In this case, the preferable ranges with respect to the maximum absorption wavelength of xcexmax(n) of an emulsion layer is applied to the preferable ranges with respect to the weight-averaged wavelength of spectral sensitivity distribution of xcexn, except that in the description of the preferable ranges of xcexn, xcexn is replaced with xcexmax(n).
In the spectral sensitivity possessed by a human, xcexC is a wavelength in a wavelength region having, so-called, a negative spectral sensitivity. Giving an interimage effect from the CL layer to another color-sensitive layer realizes spectral sensitivity similar to human eyes, and therefore, is important to attain the faithful color reproduction, which is the object of the invention.
Further, in the spectral sensitivity possessed by a human, xcexV is also a wavelength in a wavelength region having, so-called, a negative spectral sensitivity. Since xcexV is shorter wavelength than xcexC, giving an interimage effect from VL layer to another layer can realize the color fidelity in a shorter wavelength region, that is, in blue and green, and also enhance the saturation. These advantages could not be expected at all from the findings regarding a conventional silver halide color photographic material having three to four kinds of spectral property.
The CL layer and the VL layer contain a color coupler in the same manner as usual red-sensitive, green-sensitive, and blue-sensitive emulsion layers, and can form a color dye by the reduction reaction of silver halide that is contained in said layers. In this case, the colored hue provides any of the colors of orange, magenta and yellow, which are in a complementary color relationship of the absorption wavelength of the respective layers, the CL layer reveals most preferably two colors of magenta and yellow, and the VL layer reveals preferably the colors of yellow.
However, it is preferable that the CL layer and/or the VL layer, preferably the CL layer and the VL layer, do not substantially form an image dye, and it is most preferable that they do not contain a color coupler and do not reveal color by color development processing, i.e., the layers exhibit no coloring. Wherein xe2x80x9cdo not substantially form an image dyexe2x80x9d means that contribution to all color densities is extremely low, and means that it is 5% or less for all color densities and the absolute value of the color densities is 0.2 or less. It is preferable to contain no color coupler in order to generate no dye formation at all. When no color is provided, the CL layer and the VL layer become layers which exist for only providing the inter-image effect to other color sensitive emulsion layers.
The total iodine amount (I(n)) mentioned in the invention is represented by a product of the coated silver amount (AgW(n)) of silver halide grains that are contained in said color sensitive emulsion layers by the average silver iodide content (I mol %(n)), wherein n represents a sensitive color, and is selected from the characters of V, B, C, G and R. For example, when
coated silver amount of GL layer, AgW(G)=1 g/m2,
average silver iodide content of GL layer, I mol %(G)=5 mol %,
coated silver amount of CL layer, AgW(C)=0.5 g/m2, and
average silver iodide content of CL layer, I mol %(C)=12 mol %,
I(G)=5 and I(C)=6. Namely the total iodine amount that is contained in the CL layer becomes 120% of the total iodine amount that is contained in the GL layer, which means satisfying the range specified in the specification.
Such constitution is necessary for providing an adequate inter-image effect to another color sensitive layer. There is no example in which the iodine amount of silver halide grains that are contained in the layer having such an xcexn as was set to such a high value. Therefore, the advantage, i.e., color fidelity is improved by setting the iodine content to such a high value, could not be expected at all from the technical contents that were conventionally disclosed.
It is preferable that the total iodine amount I(C) of silver halide grains that are contained in the CL layer is 70% or more and 200% or less of the total iodine amount I(G) of silver halide grains that are contained in the GL layer, and more preferably 80% or more and 150% or less.
Further, it is preferable that the total iodine amount I(V) of silver halide grains that are contained in the VL layer is 50% or more and 200% or less of the total iodine amount I(B) of silver halide grains that are contained in the BL layer, and more preferably 55% or more and 150% or less.
In order to satisfy the requisite, it is required that the average silver halide contents, I mol % (C) and I mol % (V), which are contained in the CL layer and the VL layer, respectively, are set to a higher value than usual, preferably 1.2-fold or more and 6-fold or less of I mol % (G) or I mol % (B), further preferably 2-fold or more and 4-fold or less, and most preferably 2.5-fold or more and 3.5-fold or less.
The values of I mol % (C) and I mol % (V) are preferably 5 mol % or more and 40 mol % or less, more preferably 7 mol % or more and 20 mol % or less, and further more preferably 9 mol % or more and 15 mol % or less. Further, the values of I mol % (G) and I mol % (B) are preferably 0.8 mol % or more and 7 mol % or less, more preferably 1 mol % or more and 6 mol % or less, and further more preferably 1.5 mol % or more and 4 mol % or less.
The coated silver amount, AgW(C) of silver halide grains that are contained in the CL layer with respect to the coated silver amount, AgW(G) of silver halide grains that are contained in the GL layer is 0.1-fold or more and 0.6-fold or less, and preferably 0.2-fold or more and 0.5-fold or less, and more preferably 0.3-fold or more and 0.4-fold or less.
The value AgW(C) is preferably 0.05 g/m2 or more and 0.6 g/m2 or less, more preferably 0.1 g/m2 or more and 0.55 g/m2 or less, and further more preferably 0.15 g/m2 or more and 0.5 g/m2 or less. The value AgW(G) is preferably 0.5 g/m2 or more and 2.0 g/m2 or less, more preferably 0.7 g/m2 or more and 1.8 g/m2 or less, and further more preferably 0.9 g/m2 or more and 1.6 g/m2 or less.
Further, the coated silver amount, AgW(V) of silver halide grains that are contained in the VL layer with respect to the coated silver amount, AgW(B) of silver halide grains that are contained in the BL layer is 0.1-fold or more and 0.6-fold or less, and preferably 0.15-fold or more and 0.5-fold or less, and more preferably 0.2-fold or more and 0.4-fold or less.
The value AgW(V) is preferably 0.03 g/m2 or more and 0.5 g/m2 or less, more preferably 0.06 g/m2 or more and 0.4 g/m2 or less, and further more preferably 0.08 g/m2 or more and 0.3 g/m2 or less. The value AgW(B) is preferably 0.3 g/m2 or more and 1.5 g/m2 or less, more preferably 0.4 g/m2 or more and 1.3 g/m2 or less, and further more preferably 0.5 g/m2 or more and 1.1 g/m2 or less.
In order to enhance the total iodine amount of silver halide grains that are contained in the CL layer or VL layer and to improve the color fidelity over wide exposure latitude, it is preferable that each of these layers is configured with two layers or more and a plural number of silver halide emulsions are contained in a single layer. The number of layers of the CL layer and VL layer are preferably one layer or more and four layers or less, more preferably one layer or more and three layers or less, and further more preferably one layer or more and two layers or less. In a plurality of emulsions that are contained in a single layer at this time, the amount of the emulsion having a higher sensitivity is preferably 1.6-fold or more and 100-fold or less to the amount of the emulsion having a lower sensitivity, and more preferably 2-fold or more and 50-fold or less. Further, it is preferable that a plurality of emulsions that are contained in a single layer have sphere-equivalent average grain sizes of silver halide grains which differ mutually 1.2-fold or more.
The sphere-equivalent average grain size is the volume weighted average of the sphere-equivalent diameters of grains contained. The sphere-equivalent size of a grain means the diameter of a sphere that has the same volume as the volume of said grain.
The photographic material of the invention has at least one layer each of a blue-sensitive silver halide emulsion layer (BL layer), a green-sensitive silver halide emulsion layer (GL layer), a red-sensitive silver halide emulsion layer (RL layer), and a short-wavelength-green-sensitive emulsion layer (CL layer) which is a slightly shorter wavelength than that of the green-sensitive silver halide emulsion layer, or the short-wavelength-blue-sensitive emulsion layer (VL layer) which is a slightly shorter wavelength than that of the blue-sensitive silver halide emulsion layer, on a support. It is preferable, in the invention, that RL, GL and BL are coated in this order from a side nearer to the support, and it is preferable that the respective color sensitive layers have a unit configuration in which two or more of the lightsensitive emulsion layers having different speeds are contained. In particular, a configuration in which the respective color sensitive layers comprise three lightsensitive emulsion layers of a low-speed layer, a medium-speed layer, and a high-speed layer from a side nearer to the support is preferable. These are described in Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 49-15495, JP-A-59-202464 and the like.
Further, the CL layer and the VL layer can be provided, in relation to the RL, GL and BL layers, at a position that is 1) closer than the RL layer to a support, 2) intermediate between the RL layer and the GL layer, 3) intermediate between the GL layer and the BL layer, and 4) farther than the BL layer from a support.
Among these, it is most preferable that the CL layer be positioned at item 1) mentioned above. Further, when a plurality of CL layers are provided, it is preferable that either items 1) and 2), or items 1) and 3) are used in combination, and most preferable that items 1) and 3) are used in combination.
Further, it is preferable that the VL layer is provided intermediate between the GL layer and the BL layer, or at a farther position than the BL layer from a support, and most preferable that it is provided intermediate between the GL layer and the BL layer.
In one of the preferred embodiments of the invention, a lightsensitive element on which the following layers are coated on a support in this order, can be mentioned: an under coat layer/an anti-halation layer/a 1st intermediate layer/a CL layer unit/a 2nd intermediate layer/a RL layer unit (comprising, from the side closer to the support, three layers of a low-speed red-sensitive layer/a medium-speed red-sensitive layer/a high-speed red-sensitive layer)/a 3rd intermediate layer/a GL unit (comprising, from the side closer to the support, three layers of a low-speed green-sensitive layer/a medium-speed green-sensitive layer/a high-speed green-sensitive layer)/a yellow filter layer/a VL layer/a 4th intermediate layer/a BL layer unit (comprising, from the side closer to the support, three layers of a low-speed blue-sensitive layer/a medium-speed blue-sensitive layer/a high-speed blue-sensitive layer)/a 1st protective layer/a 2nd protective layer/a 3rd protective layer.
In the above embodiment, each of the 1st, 2nd, 3rd and 4th intermediate layers may be in a configuration of one layer or two or more layers.
The intermediate layer may contain a coupler and a DIR compound such as those described in the specifications of JP-A""s-61-43748, 59-113438, 59-113440, 61-20037 and 61-20038. The intermediate layer may also contain a color mixing prevention agent, as usually do so.
In the photographic material of the invention, a non-color forming inter layer may be included in a lightsensitive unit having the same color sensitivity may. Further, the interlayer preferably contains a compound capable of being selected as a competing compound to be described later.
It is also preferable that the photographic material of the invention may have a three-layered protective layer structure comprising 1st, 2nd and 3rd protective layers. When the number of the protective layers is two or three, the 2nd protective layer preferably contains fine grain silver halide having an equivalent sphere average size of 0.10 xcexcm or less. The silver halide is preferably silver bromide or silver iodobromide.
The lightsensitive emulsion layers other than the CL layer which are mentioned in the specification substantially mean the RL, GL, BL and VL layers. A non-lightsensitive layer having color mixing prevention ability which is provided between these layers and the CL layer has an effect in which a developing agent in an oxidized form generated from one layer does not transfer to a neighboring layer across the non-lightsensitive layer.
The non-lightsensitive layer is a layer other than a lightsensitive layer in which silver halide grains contained therein respond to photo stimulation to carry out latent image formation.
The layer having a color mixing prevention ability preferably is a gelatin layer with a film thickness of 0.5 xcexcm or more and 5 xcexcm or less and/or contains a competing compound. More preferable film thickness is 1 xcexcm or more and 4 xcexcm or less, and further preferably 1.5 xcexcm or more and 3 xcexcm or less.
The layer having a color mixing prevention ability preferably contains a compound that reacts with a color developing agent in an oxidized form in competition with an image forming coupler as a competing compound and does not form an dye image. Specifically, the layer preferably contains reducing compounds such as hydroquinones, catechols, hydrazines, and sulfonamidephenols, or compounds capable of coupling with a developing agent in an oxidized form but does not substantially form color images (e.g., colorless couplers disclosed in German Patent No. 1,155,675, British Patent 861,138, U.S. Pat. Nos. 3,876,428, and 3,912,513, or couplers whose dyes produced therefrom flow out during a processing step, such as those disclosed in JP-A-6-83002).
More preferable competing compounds are hydroquinone compounds and hydrazine compounds, and hydroquinone compounds are more preferable. The most preferable hydroquinone compounds are those represented by the general formula (A) described in JP-A-10-026816 
In the general formula (A), R represents an alkyl group, and X represents a halogen atom, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an acylamido group, a sulfonamido group, a carbamoyl group, a sulfamoyl group, a sulfonyl group, an ureido group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, an acyl group, or a heterocyclic group. n represents an integer of 0 to 3, and when n is 2 to 3, a plurality of X""s may be the same or different, respectively.
Further, the addition amount of these competing compounds to an intermediate layer sandwiched between a lightsensitive layer and the nearest lightsensitive layer thereto is 50 mg/m2 or more and 1000 mg/m2 or less. When the intermediate layer is configured with two layers or more, the addition amount is the total amount of the layers. More preferably the addition amount is 150 mg/m2 or more and 700 mg/m2 or less, and 250 mg/m2 or more and 500 mg/m2 or less is most preferable. Such a coating amount of the competing compound is more than that used in the conventional intermediate layer. It could not be expected that providing a non-light sensitive layer having a color mixing prevention ability between the CL layer and a lightsensitive layer other than the CL layer as mentioned above, and using a large amount of the competing compound in the non-photosensitive layer could attain highly faithful color reproduction.
Usually, the maximum absorption wavelength of the RL layer or the weight-averaged wavelength of spectral sensitivity distribution (xcexR) is 580 nmxe2x89xa6xcexRxe2x89xa6680 nm, while in the invention, xcexR is preferably 550 nm xe2x89xa6xcexRxe2x89xa6670 nm. It is more preferably 580 nmxe2x89xa6xcexRxe2x89xa6660 nm, and most preferably 600 nmxe2x89xa6xcexRxe2x89xa6650 nm.
The photographic material of the invention contains an image forming coupler. The image forming coupler means a coupler that forms an image forming dye by coupling with an aromatic primary amine color developing agent in an oxidized form, and a color image is generally obtained using a yellow coupler, a magenta coupler and a cyan coupler in combination.
The image forming coupler of the invention is preferably used by being added in a lightsensitive emulsion layer sensitive to light which is in the relation of complementary color to the color hue of the coupler. Namely, the yellow coupler is added to the blue-sensitive emulsion layer, the magenta coupler to the green-sensitive emulsion layer, and the cyan coupler to the red-sensitive emulsion layer. Further, it is preferable for purposes of improving the shadow description property and the like that the coupler that is not in relation of complementary color is used in combination, e.g., the cyan coupler or the yellow coupler is used together in the green-sensitive emulsion layer in accordance with the objective, etc. The addition of the coupler which is not in the relation of complementary color differs depending on the color-forming efficiency of the coupler, but is generally 1 mol % or more and 15 mol % or less based on a coupler which is in relation of complementary color, preferably 2 mol % or more and 12 mol % or less, and more preferably 3 mol % or more and 10 mol % or less.
Yellow couplers:
couplers represented by formulas (I) and (II) in EP502,424A;
couplers (particularly Y-28 on page 18) represented by formulas (1) and (2) in EP513,496A;
couplers represented by formula (I) in claim 1 of EP568,037A;
couplers represented by formula (I) in column 1, lines 45 to 55 of U.S. Pat. No. 5,066,576;
couplers represented by formula (I) in paragraph 0008 of JP-A-4-274425;
couplers (particularly D-35) described in claim 1 on page 40 of EP498,381A1;
couplers (particularly Y-1 and Y-54) represented by formula (Y) on page 4 of EP447,969A1;
couplers represented by formulas (II) to (IV) in column 7, lines 36 to 58 of U.S. Pat. No. 4,476,219; and so on
Magenta couplers:
couplers described in JP-A-3-39737 (e.g., L-57, L-68, and L-77);
couplers described in EP456,257 (e.g., A-4-63, and A-4-73 and A-4-75;
couplers described in EP486,965 (e.e., M-4, M-6, and M-7;
couplers described in EP571,959A (e.e., M-45);
couplers described in JP-A-5-204106 (e.g., M-1);
couplers described in JP-A-4-362631 (e.g., M-22);
couplers represented by general formula (MC-1) described in JP-A-11-119393 (e.g., CA-4, CA-7, CA-12, CA-15, CA-16, and CA-18); and so on
Cyan couplers:
couplers described in JP-A-4-204843 (e.g., CX-1, -3, -4, -5, -11, -12, -14, and -15);
couplers described in JP-A-4-43345 (e.g., C-7, -10, -34 and, -35, and (I-1) and (I-17);
couplers represented by formulas (Ia) or (Ib) in claim 1 of JP-A-6-67385;
couplers represented by general formula (PC-1) described in JP-A-11-119393 (e.g., CB-1, CB-4, CB-5, CB-9, CB-34, CB-44, CB-49 and CB-51);
couplers represented by general formula (NC-1) described in JP-A-11-119393 (e.g., CC-1 and CC-17); and so on
These couples can be introduced into a photographic material by various known dispersing methods. It is preferable that an water-in-oil dispersing method by dissolving a coupler to a high-boiling organic solvent, in combination with a low-boiling solvent, if necessary, and dispersing it by emulsification to a gelatin solution, thereby adding it to a silver halide emulsion.
Examples of the high-boiling solvent used in this oil-in-water dispersion method are described in, e.g., U.S. Pat. No. 2,322,027, the disclosure of which is herein incorporated by reference. Practical examples of steps, effects, and impregnating latexes of a latex dispersion method as one polymer dispersion method are described in, e.g., U.S. Pat. No. 4,199,363, West German Patent Application (OLS) Nos. 2,541,274 and 2,541,230, JP-B-53-41091, and EP029104, the disclosures of which are herein incorporated by reference. Dispersion using an organic solvent-soluble polymer is described in PCT International Publication WO88/00723, the disclosure of which is herein incorporated by reference.
Examples of the high-boiling solvent usable in the abovementioned oil-in-water dispersion method are phthalic acid esters (e.g., dibutylphthalate, dioctylphthalate, dicyclohexylphthalate, bis(2-ethylhexyl)phthalate, decylphthalate, bis(2,4-di-tert-amylphenyl)isophthalate, and bis(1,1-diethylpropyl)phthalate), esters of phosphoric acid and phosphonic acid (e.g., diphenylphosphate, triphenylphosphate, tricresylphosphate, 2-ethylhexyldiphenylphosphate, dioctylbutylphosphate, tricyclohexylphosphate, tri-2-ethylhexylphosphate, tridodecylphosphate, and bis(2-ethylhexyl)phenylphosphate), benzoic acid esters (e.g., 2-ethylhexylbenzoate, 2,4-dichlorobenzoate, dodecylbenzoate, and 2-ethylhexyl-p-hydroxybenzoate), amides (e.g., N,N-diethyldodecaneamide, N,N-diethyllaurylamide, N,N,N,N-tetrakis(2-ethylhexyl)isophthalic acid amide), alcohols and phenols (e.g., isostearylalcohol and 2,4-di-tert-amylphenol), aliphatic esters (e.g., dibutoxyethyl succinate, bis(2-ethylhexyl) succinate, 2-hexyldecyl tetradecanoate, tributyl citrate, diethyl azelate, isostearyl lactate, and trioctyl tosylate), aniline derivatives (e.g., N,N-dibutyl-2-butoxy-5-tert-octylaniline), chlorinated paraffins (paraffins containing 10% to 80% of chlorine), trimesic acid esters (e.g., tributyl trimesate), dodecylbenzene, diisopropylnaphthalene, phenols (e.g., 2,4-di-tert-amylphenol, 4-dodecyloxyphenol, 4-dodecyloxycarbonylphenol, and 4-(4-dodecyloxyphenylsulfonyl)phenol), carboxylic acids (e.g., 2-(2,4-di-tert-amylphenoxy butyric acid and 2-ethoxyoctanedecanoic acid), alkylphosphoric acids (e.g., bis(2-ethylhexyl)phosphoric acid and diphenylphosphoric acid). In addition to the above high-boiling solvents, compounds described in, e.g., JP-A-6-258803, the disclosure of which is herein incorporated by reference, can also be preferably used as high-boiling solvents.
The weight ratio of a high-boiling organic solvent to a coupler is preferably 0 to 2.0, more preferably, 0 to 1.0, and most preferably, 0 to 0.4.
As a co-solvent, it is also possible to use an organic solvent (e.g., ethyl acetate, butyl acetate, ethyl propionate, methylethylketone, cyclohexanone, 2-ethoxyethylacetate, and dimethylformamide) having a boiling point of 30xc2x0 C. to about 160xc2x0 C.
The content of each of yellow, magenta and cyan couplers in a photographic material is preferably 0.01 to 10 g, more preferably 0.1 to 2 g per m2. A proper content of each of the couplers, per mol of silver halide contained in an emulsion layer(s) having sensitivity to the same color, is 1xc3x9710xe2x88x923 to 1 mol, and preferably 2xc3x9710xe2x88x923 to 3xc3x9710xe2x88x921 mol.
When the lightsensitive layer is composed of a unit structure having two or more lightsensitive emulsion layers different in speed, the content, per mol of silver halide, of the coupler of the invention preferably is such a configuration that the layer having higher speed contains more couplers.
To prevent deterioration of the photographic properties caused by formaldehyde gas, the photographic material of the invention preferably contains a compound described in U.S. Pat. Nos. 4,411,987 or 4,435,503, which can react with and fix formaldehyde gas.
The emulsion used in the silver halide color photographic material of the invention preferably contains the tabular silver halide grains (hereinafter also referred to as xe2x80x9ctabular grainsxe2x80x9d) having an aspect ratio of 1.5 or more and less than 100. Herein, the tabular silver halide grains are the general name of silver halide grains having one twin plane or two or more of the parallel twin planes. The twin plane means a (111) face on the two sides of which ions at all lattice points have a mirror image relationship. The tabular grain is constituted by two opposing and parallel main planes and side faces linking these main planes. When the tabular grain is viewed in a direction perpendicular to the main plane, the main plane has any of triangular, hexagonal or round circular shapes of triangular or hexagonal, the triangular shape has the triangular opposing and parallel main plane, the hexagonal surface has the hexagonal one, and the circular shape has the circular one.
The aspect ratio of the tabular grain is a value obtained by dividing the grain diameter by the thickness. The measurement of thickness of the tabular grain can be easily carried out by depositing a metal from the oblique direction of the grain together with a latex for reference, measuring the length of its shadow on an electron microscope photograph and calculating referring to the length of shadow of the latex.
The grain diameter of the invention is the diameter of a circle having an area equal to the projected area of the parallel main planes of the grain.
The projected area of the grain is obtained by measuring an area on the electron microscope photograph and compensating a photographing magnification.
The diameter of the tabular grain is preferably 0.3 to 5.0 xcexcm. The thickness of the tabular grain is preferably 0.05 to 0.5 xcexcm.
The sum of the projected areas of the tabular grains used in the present invention preferably occupies 50% or more, more preferably 80% or more, of the total projected area of all the silver halide grains in the emulsion. Further, the aspect ratios of the tabular grains which occupy these fixed areas are preferably 1.5 to less than 100, more preferably 2 to less than 20, and further preferably 2 to less than 8.
Further, when monodisperse tabular grains are used, further preferable effect happens to be obtained. The structure and preparation process of the monodisperse tabular grains are according to, for example, JP-A-63-151618 and the like, and when its shape is simply described, 70% or more of all the projected areas of silver halide grains is a hexagonal shape in which a ratio of the length of a side having the maximum length to that of a side having the minimum length in the main plane is 2 or less, and is occupied by the tabular silver halide grains having two parallel planes as outer planes. Further, it has the monodisperse property in which the variation coefficient of the grain diameter distribution of said hexagonal tabular silver halide grain, i.e., a value obtained by dividing the deviation (standard deviation) of grain diameters by the average grain diameter and then multiply with 100, is 20% or less.
In the present invention, the tabular grains preferably have dislocation lines.
The dislocation in the tabular grains can be observed by the direct method using a transmission electron microscope at low temperatures as described in, for example, J. F. Hamilton, Phot. Sci. Eng., 11, 57 (1967) and T. Shiozawa, J. Soc. Phot. Sci. Tech. Japan, 35, 213 (1972). Illustratively, silver halide grains are harvested from the emulsion with the care that the grains are not pressurized with such a force that dislocation lines occur on the grains, are put on a mesh for electron microscope observation and, while cooling the specimen so as to prevent damaging (printout, etc.) by electron beams, are observed by the transmission method. The greater the thickness of the above grains, the more difficult the transmission of electron beams. Therefore, the use of an electron microscope of high voltage type (at least 200 kV on the grains of 0.25 xcexcm in thickness) is preferred for ensuring clearer observation. The thus obtained photograph of grains enables determining the position and number of dislocation lines in each grain viewed in the direction perpendicular to the main planes.
The position of the dislocation of the tabular grains used in the present invention arises from x % of the distance between the center and the side to the side, along the long axis of the tabular grain. The value x is preferably 10xe2x89xa6x less than 100, more preferably 30xe2x89xa6x less than 98, and much more preferably 50xe2x89xa6x less than 95. In this instance, the figure created by binding the positions from which the dislocation lines start is nearly similar to the configuration of the grain. The created figure may be one that is not a complete similar figure but deviated. The direction of the dislocation lines is roughly in the direction from the center to the sides, but they often windle.
Regarding the number of dislocation lines in the tabular grains used in the present invention, it is preferable that grains having 10 or more dislocation lines are present in an amount of 50% (by number of grains) or more. More preferably, grains having 10 or more dislocation lines are present in an amount of 80% (by number of grains) or more, and especially preferably those having 20 or more dislocation lines in an amount of 80% (by number of grains) or more.
The preparation process of the tabular grain used in the present invention is described.
The tabular grain used in the present invention can be prepared by improving methods described in xe2x80x9cCleave, Photography Theory and Practice (1930), page 13xe2x80x9d, xe2x80x9cGutuff, Photographic Science and Engineering Vol.14, pages 248-257 (1970)xe2x80x9d, U.S. Pat. Nos. 4,434,226, 4,414,310, 4,433,048 and 4,439,520, and BG 2,112,157 and the like.
Any of the silver halide compositions such as silver bromide, silver iodobromide, silver iodochlorobromide and silver chlorobromide may be used for the tabular silver halide grain used in the present invention. The preferable silver halide composition is silver iodobromide or silver iodochlorobromide containing 30 mol % or less of silver iodide.
The silver halide grains used in the present invention may have a multiple structure of a double structure or more, for example, a quintuple structure, concerning the intra-grain silver halide composition. The structure refers to a structure concerning the intra-grain silver iodide distribution, and it is indicated that the difference in silver iodide content between each structure is of 1 mol % or more. This intra-grain silver iodide distribution structure can be basically obtained by calculations from the prescribed value in the grain preparation step. In the interface between layers of the structure, the silver iodide content can change either abruptly or moderately. The EPMA (Electron Probe Micro Analyzer) method is usually effective to confirm this structure, although the measurement accuracy of analysis must be taken into consideration. By forming a sample in which emulsion grains are dispersed so as not to contact each other and analyzing radiated X-rays by radiating an electron beam, elements in a micro region irradiated with the electron beam can be analyzed. The measurement is preferably performed under cooling at low temperatures in order to prevent damage to the sample by the electron beam. By this method, the intra-grain silver iodide distribution of a tabular grain can be analyzed when the grain is viewed in a direction perpendicular to its main planes. Additionally, when a specimen obtained by hardening a sample and cutting the sample into a very thin piece using microtome is used, the intra-grain silver iodide distribution in the section of a tabular grain can be analyzed.
In the nucleation of the grain formation, to use a gelatin having a small methionine content disclosed in U.S. Pat. Nos. 4,713,320 and 4,942,120; to perform the nucleation at a high pBr disclosed in U.S. Pat. No. 4,914,014; and to perform the nucleation in a short time disclosed in JP-A-2-222940 are very effective for the preparation of tabular grains. In the ripening step, to perform the ripening in the presence of a base of a low concentration disclosed in U.S. Pat. No. 5,254,453 and to perform the ripening at a high pH disclosed in U.S. Pat. No. 5,013,641 may be effective for the ripening step of the emulsions of the invention.
The method of forming tabular grains using the polyalkyleneoxide compounds described in U.S. Pat. Nos. 5,147,771, 5,147,772, 5,147,773, 5,171,659, 5,210,013, and 5,252,453, is preferably used in the core grain preparation used in the present invention.
To obtain high-aspect-ratio monodisperse tabular grains, gelatin is sometimes additionally added during grain formation. The gelatin used at that time is preferably chemically modified gelatin described in JP-A""s-10-148897 and 11-143002 or gelatin having a small methionine content described in U.S. Pat. Nos. 4,713,320 and 4,942,120. The former chemically modified gelatin is a gelatin characterized in that at least two carboxyl groups are newly introduced when an amino group in the gelatin is chemically modified. It is preferable to use succinated gelatin or trimellitated gelatin. This chemically modified gelatin is added preferably before the growth step, and more preferably immediately after nucleation. The addition amount thereof is 50% or more, preferably 70% or more of the weight of the total dispersing medium used during grain formation.
Examples of silver halide solvents which can be used in the present invention include organic thioethers (a) described in U.S. Pat. Nos. 3,271,157, 3,531,286 and 3,574,628 and JP-A""s-54-1019 and 54-158917; thiourea derivatives (b) described in JP-A""s-53-82408, 55-77737 and 55-2982; silver halide solvents having a thiocarbonyl group interposed between an oxygen or sulfur atom and a nitrogen atom (c) described in JP-A-53-144319; imidazoles (d) described in JP-A-54-100717; sulfites (e); ammonia (f); and thiocyanates (g). Especially preferred solvents are thiocyanates, ammonia and tetramethylthiourea. Although the amount of added solvent depends on the type thereof, in the case of, for example, a thiocyanate, the preferred amount is in the range of 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x922 mol per mol of silver halides. Basically, when a washing step is provided after the first shell formation as described above, the solvent can be removed regardless of the kind of a solvent used.
The dislocation of the tabular grain used in the present invention is introduced by providing a high iodine phase to the inside of the grain.
The high iodine phase is a silver halide solid solution containing iodine, and in this case, silver iodide, silver iodobromide and silver chloroiodobromide are preferable as the silver halide, silver iodide or silver iodobromide is preferable and silver iodide is preferable in particular.
The amount of silver halide which forms the high-iodide phase is 30 mol % or less of the silver amount of all the grains, and further preferably 10 mol % or less.
A phase grown at the outside of the high iodine phase is required to have a lower silver iodide contents than that in the high iodine phase, and the preferable silver iodide content is 0 to 12 mol %, further preferably 0 to 6 mol %, and most preferably 0 to 3 mol %.
As the preferable method of forming the high iodine phase, there is a method of forming the phase by adding an emulsion containing silver iodobromide or a silver iodide fine grains (hereinafter referred to as silver iodide fine grain emulsion). Fine grains preliminarily prepared can be used as these fine grains, and the fine grains immediately after preparation can be more preferably used.
A case of using the fine grains preliminarily prepared is firstly illustrated. In this case, there is a method of adding the fine grains preliminarily prepared, ripening and dissolving them. As the more preferable method, there is a method of adding the silver iodide fine grain emulsion, and then adding an aqueous silver nitrate solution, or an aqueous silver nitrate solution and an aqueous halogen solution. In this case, the dissolution of the fine grains is accelerated by the addition of the aqueous silver nitrate solution. It is preferred that the silver iodide fine grain emulsion be added abruptly.
The abrupt addition of the silver iodide fine grain emulsion means the addition of the silver iodide fine grain emulsion within preferably 10 minutes. It means the addition within 7 minutes more preferably. The condition can be changed according to the temperature, pBr and pH of a system added, the kind and concentration of protective colloid agents such as a gelatin and the like, the presence or absence, kind, and concentration of the silver halide solvent, and the like, but the shorter period is preferable as described above. It is preferable that the addition of an aqueous silver salt solution such as silver nitrate or the like is not substantially carried out at the addition. The temperature of the system at the addition is preferably 40xc2x0 C. or more and 90xc2x0 C. or less, and preferably 50xc2x0 C. or more and 80xc2x0 C. or less in particular.
The composition of fine grains contained in the silver iodide fine grain emulsion may be substantially silver iodide, and silver bromide and/or silver chloride may be contained so far as it can be a mix crystal. Preferable is 100% silver iodide. Silver iodide occasionally takes a xcex2-form, a xcex3-form and an xcex1-form or an xcex1-form analogous structure as described in U.S. Pat. No. 4,672,026, in its crystal structure. In the present invention, there is no limitation of the crystal structure in particular, a mixture of the xcex2-form and the xcex3-form is used, and the xcex2-form is further preferably used. The silver iodide fine grain emulsion after a usual washing step with water is preferably used. The silver iodide fine grain emulsion can be easily formed by a method described in U.S. Pat. No. 4,672,026. The grain formation is carried out by making the pI value at the grain formation constant. The double jet addition method of the aqueous silver salt solution and the aqueous iodide salt solution is preferable. Herein, pI is a logarithm of the reciprocal of Ixe2x88x92 ion concentration of the system. The temperature, pI, pH, the kind and concentration of protective colloid agents such as a gelatin and the like, the presence or absence, kind, and concentration of the silver halide solvent, and the like are not limited in particular, but it is suitable for the present invention that the size of grains is 0.1 xcexcm or less and more preferably 0.07 xcexcm or less. Since the grains are fine grains, the grain shape is not perfectly specified, but the variation coefficient of the grain size distribution is preferably 25% or less. When it is 20 or less, the advantage of the invention is remarkable. Herein, the size and the size distribution of the fine grains are directly determined by putting the fine grains on a mesh for electron microscope observation, and observing by not a carbon replica method but a permeation method. Since the grain size is small, measurement error becomes great by observation according to the carbon replica method. The grain size is defined as the diameter of a circle having a projected area equal to the grain observed. The size distribution of grains is also determined using the circle diameter having the equal projected area. The most effective fine grain in the present invention is that having a grain size of 0.06 xcexcm or less and 0.02 xcexcm or more, and the variation coefficient of a size distribution of grains of 18% or less.
In the formation of the silver iodide fine grain emulsion, after the above-mentioned grain formation, a usual washing with water described in U.S. Pat. No. 2,614,929 is preferably carried out to the silver iodide fine grain emulsion, and pH, pI, the concentration of protective colloid agents such as a gelatin and the like and the concentration of the silver iodide contained are carried out. The pH is preferably 5 or more and 7 or less. The pI value is preferably set at a pI value in which the solubility of silver iodide is minimum, or at a higher pI value than the value. As the protective agent, a usual gelatin having an average molecular weight of about 100,000 is preferably used. A low-molecular-weight gelatin having an average molecular weight of 20,000 or less is also preferably used. Further, there is occasionally a suitable case if the above-mentioned gelatins having different molecular weights are used in mixture. The amount of the gelatin per one kg of the emulsion is preferably 10 g or more and 100 g or less. 20 g or more and 80 g or less is more preferable. The amount of silver converted to silver atom per kg of the emulsion is preferably 10 g or more and 100 g or less. 20 g or more and 80 g or less is more preferable. As the amount of the gelatin and/or the amount of silver, a value suitable for abruptly adding the silver iodide fine grain emulsion is preferably selected.
The silver iodide fine grain emulsion is usually added by preliminarily being dissolved, and the stirring efficiency of the system at addition is required to be adequately enhanced. The rotational number of stirring is preferably set higher than usual. The addition of a defoaming agent is effective for preventing the generation of foam at stirring. Specifically, a defoaming agent described in Examples and the like of U.S. Pat. No. 5,275,929 is used.
When the fine grains immediately after preparation is used, a detail concerning a mixer for forming the silver halide fine grain can be referred to the description of JP-A-10-43570.
For the silver halide fine grains of the invention, it is preferable that the variation coefficient of the silver iodide contents distribution is 20% or less. 15% or less is preferable, and 10% or less is preferable in particular. When the variation coefficient is more than 20%, it does not have high contrast, and when a pressure is applied, it is not preferable because the decrease of sensitivity becomes also great. The silver iodide content of each grain can be measured by analyzing the composition of each of grains using an X-ray micro analyzer. The variation coefficient of the silver iodide content distribution between the respective grains is a value determined by the relation equation (standard deviation/average silver iodide content)xc3x97100=variation coefficient using the standard deviation of the silver iodide content and the average silver iodide content when the silver iodide content of at least 100 or more, more preferably 200 or more and in particular preferably 300 or more of the emulsion grains is measured. The measurement of the silver iodide contents of individual grains is described in, for example, EP 147,868. There is a correlation or no correlation between the silver iodide content Yi (mol) of the individual grains and the equivalent-sphere diameter Xi (xcexcm) of the respective grains, but no correlation is desirable.
The silver halide emulsion of the invention is preferably provided with a positive hole-capturing zone in at least a portion of the inside of the silver halide grains. The positive hole-capturing zone of the invention indicates a region having a function of capturing a positive hole generated in pair with photo-electron generated by, for example, photo-excitation. Such positive hole-capturing zone is defined in the present invention as a zone provided by an intentional reduction sensitization.
The intentional reduction sensitization in the present invention means an operation of introducing a positive hole-capturing silver nuclei into a portion or all of the inside of the silver halide grains by adding a reduction sensitizing agent. The positive hole-capturing silver nuclei means a small silver nuclei having a little development activity, and the recombination loss at a lightsensitive process is prevented by the silver nuclei and the sensitivity can be enhanced.
Examples of known reduction sensitizers include stannous salts, ascorbic acid and derivatives thereof, amines and polyamines, hydrazine derivatives, formamidinesulfinic acid, silane compounds and borane compounds. In the reduction sensitization employed in the present invention, appropriate one may be selected from among these known reduction sensitizers and used or at least two may be selected and used in combination. Preferred reduction sensitizers are stannous chloride, thiourea dioxide, dimethylaminoborane, ascorbic acid and derivatives thereof. Although the addition amount of reduction sensitizer must be selected because it depends on the emulsion manufacturing conditions, it is preferred that the addition amount range from 10xe2x88x927 to 10xe2x88x923 mol per mol of silver halide.
The reduction sensitizer is dissolved in water or any of organic solvents such as alcohols, glycols, ketones, esters and amides and added during the grain growth.
In the present invention, the positive hole-capturing silver nuclei is formed preferably by adding a reduction sensitizer at a time of after nucleation and after the completion of the physical ripening, and immediately before the initiation of grain formation. However, the positive hole-capturing silver nuclei can also be introduce on the grain surface by adding a reduction sensitizer on and after the completion of the grain formation.
When a reduction sensitizer is added during grain formation, some silver nuclei formed can stay inside a grain, but some ooze out to form silver nuclei on the grain surface. In the present invention, these oozing silver nuclei are preferably used as positive hole-capturing silver nuclei.
In the present invention, when the intentional reduction sensitization is performed during a step in the midst of grain growth in order to form the positive hole-capturing nuclei inside the silver halide grain, it is necessary to perform the intentional reduction sensitization in the presence of a compound represented by general formula (I-1) or general formula (I-2).
Herein, the step in the midst of the grain growth does not include the step after the final desalting is performed. For example, a step of chemical sensitization in which silver halide grains grow as a result of the addition of a silver salt solution and fine grain silver halide, is not included. 
In formulas (I-1) and (I-2), each of W51 and W52 independently represents a sulfo group or hydrogen atom. However, at least one of W51 and W52 represents a sulfo group. A sulfo group is generally an alkali metal salt such as sodium or potassium or a water-soluble salt such as ammonium salt. Favorable practical examples are 3,5-disulfocatechol disodium salt, 4-sulfocatechol ammonium salt, 2,3-dihydroxy-7-sulfonaphthalene sodium salt, and 2,3-dihydroxy-6,7-jisulfonaphthalen potassium salt. A preferred addition amount can vary in accordance with, e.g., the temperature, pBr, and pH of the system to which the compound is added, the type and concentration of a protective colloid agent such as gelatin, and the presence/absence, type, and concentration of a silver halide solvent. Generally, the addition amount is preferably 0.0005 to 0.5 mol, and more preferably, 0.003 to 0.02 mol per mol of a silver halide.
An oxidizer capable of oxidizing silver is preferably used during the process of producing the emulsion for use in the present invention (hereinafter also referred to as the emulsion of the invention). The silver oxidizer is a compound having an effect of acting on metallic silver to thereby convert the same to silver ion. A particularly effective compound is one that converts very fine silver grains, formed as a by-product in the step of forming silver halide grains and the step of chemical sensitization, into silver ions. Each silver ion produced may form a silver salt sparingly soluble in water, such as a silver halide, silver sulfide or silver selenide, or may form a silver salt easily soluble in water, such as silver nitrate. The silver oxidizer may be either an inorganic or an organic substance. Examples of suitable inorganic oxidizers include ozone, hydrogen peroxide and its adducts (e.g., NaBO2.H2O2.3H2O, 2NaCO3.3H2O2, Na4P2O7.2H2O2 and 2Na2SO4.H2O2.2H2O), peroxy acid salts (e.g., K2S2O8, K2C2O6 and K2P2O8), peroxy complex compounds (e.g., K2[Ti(O2)C2O4].3H2O, 4K2SO4.Ti(O2)OH.SO4.2H2O and Na3[VO(O2)(C2H4)2]. 6H2O), permanganates (e.g., KMnO4), chromates (e.g., K2Cr2O7) and other oxyacid salts, halogen elements such as iodine and bromine, perhalogenates (e.g., potassium periodate), salts of high-valence metals (e.g., potassium hexacyanoferrate (II)) and thiosulfonates.
Examples of suitable organic oxidizers include quinones such as p-quinone, organic peroxides such as peracetic acid and perbenzoic acid and active halogen-releasing compounds (e.g., N-bromosuccinimide, chloramine T and chloramine B).
Oxidizers preferred in the present invention are inorganic oxidizers selected from among ozone, hydrogen peroxide and its adducts, halogen elements and thiosulfonates and organic oxidizers selected from among quinones. Especially preferably, the oxidizers are thisosulfonate such as those described in JP-A-2-191938.
The addition of the oxidizer to silver may be performed at any time selected from before the initiation of the intentional reduction sensitization, during reduction sensitization, immediately before the termination of reduction sensitization and immediately after the termination of reduction sensitization. The addition of the oxidizer to silver may be performed several times separately. The addition amount, although it varies depending on a kind of the oxidizer, is preferably in a range of 1xc3x9710xe2x88x927 to 1xc3x9710xe2x88x923 mol per mol of silver halide.
It is advantageous to use gelatin as a protective colloid for use in preparation of emulsions of the invention or as a binder for other hydrophilic colloid layers. However, another hydrophilic colloid can also be used in place of gelatin.
Examples of the hydrophilic colloid are protein, such as a gelatin derivative, a graft polymer of gelatin and another high polymer, albumin, and casein; sugar derivatives, such as cellulose derivatives, e.g., cellulose sulfates, hydroxyethylcellulose, and carboxymethylcellulose, soda alginate, and starch derivatives; and a variety of synthetic hydrophilic high polymers, such as homopolymers or copolymers, e.g., polyvinyl alcohol, polyvinyl alcohol with partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, and polyvinylpyrazole.
Examples of gelatin are lime-processed gelatin, acid-processed gelatin, and enzyme-processed gelatin described in Bull. Soc. Sci. Photo. Japan, 16, page 30 (1966). In addition, a hydrolyzed product or an enzyme-decomposed product of gelatin can also be used.
It is preferable to wash with water an emulsion of the present invention to desalt, and disperse into a newly prepared protective colloid. Although the temperature of washing can be selected in accordance with the intended use, it is preferably 5xc2x0 C. to 50xc2x0 C. Although the pH of washing can also be selected in accordance with the intended use, it is preferably 2 to 10, and more preferably, 3 to 8. The pAg of washing is preferably 5 to 10, though it can also be selected in accordance with the intended use. The washing method can be selected from noodle washing, dialysis using a semipermeable membrane, centrifugal separation, coagulation precipitation, and ion exchange. The coagulation precipitation can be selected from a method using sulfate, a method using an organic solvent, a method using a water-soluble polymer, and a method using a gelatin derivative.
In the preparation of the emulsion of the invention, it is preferable to make salt of metal ion exist, for example, during grain formation, desalting, or chemical sensitization, or before coating in accordance with the intended use. The metal ion salt is preferably added during grain formation when doped into grains, and after grain formation and before completion of chemical sensitization when used to decorate the grain surface or used as a chemical sensitizer. The salt can be doped in any of an overall grain, only the core, the shell, or the epitaxial portion of a grain, and only a substrate grain. Examples of the metal are Mg, Ca, Sr, Ba, Al, Sc, Y, La, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Rh, Pd, Re, Os, Ir, Pt, Au, Cd, Hg, Tl, In, Sn, Pb, and Bi. These metals can be added as long as they are in the form of salt that can be dissolved during grain formation, such as ammonium salt, acetate, nitrate, sulfate, phosphate, hydroxide, 6-coordinated complex salt, or 4-coordinated complex salt. Examples are CdBr2, CdCl2, Cd(NO3)2, Pb(NO3)2, Pb(CH3COO)2, K3[Fe(CN)6], (NH4)4[Fe(CN)6], K4[Fe(CN)6], K2IrCl6, K3IrCl6, (NH4)3RhCl6, and K4Ru(CN)6. The ligand of a coordination compound can be selected from halo, aquo, cyano, cyanate, thiocyanate, nitrosyl, thionitrosyl, oxo, and carbonyl. These metal compounds can be used either singly or in the form of a combination of two or more types of them.
The metal compounds are preferably dissolved in an appropriate solvent, such as methanol or acetone, and added in the form of a solution. To stabilize the solution, an aqueous hydrogen halogenide solution (e.g., HCl or HBr) or an alkali halide (e.g., KCl, NaCl, KBr, or NaBr) can be added. It is also possible to add acid or alkali if necessary. The metal compounds can be added to a reactor vessel either before or during grain formation. Alternatively, the metal compounds can be added to a water-soluble silver salt (e.g., AgNO3) or an aqueous alkali halide solution (e.g., NaCl, KBr, or KI) and added in the form of a solution continuously during formation of silver halide grains. Furthermore, a solution of the metal compounds can be prepared independently of a water-soluble salt or an alkali halide and added continuously at a proper timing during grain formation. It is also possible to combine several different addition methods.
It is sometimes useful to perform a method of adding a chalcogen compound during preparation of an emulsion, such as described in U.S. Pat. No. 3,772,031. In addition to S, Se, and Te, cyanate, thiocyanate, selenocyanic acid, carbonate, phosphate, and acetate can be present.
In the silver halide grains used in the invention, at least one of chalcogen sensitization including sulfur sensitization and selenium sensitization, and noble metal sensitization including gold sensitization and palladium sensitization, and reduction sensitization can be performed at any point during the process of preparing a silver halide emulsion. The use of two or more different sensitizing methods is preferable.
Several different types of emulsions can be prepared by changing the timing at which the chemical sensitization is performed. The emulsion types are classified into: a type in which a chemical sensitization nucleus is embedded inside a grain, a type in which it is embedded in a shallow position from the surface of a grain, and a type in which it is formed on the surface of a grain. In emulsions of the present invention, the position of a chemical sensitization nucleus can be selected in accordance with the intended use. However, it is preferable to form at least one type of a chemical sensitization nucleus in the vicinity of the surface.
One chemical sensitization which can be preferably performed in the present invention is chalcogen sensitization, noble metal sensitization, or a combination of these. The sensitization can be performed by using active gelatin as described in T. H. James, The Theory of the Photographic Process, 4th ed., Macmillan, 1977, pages 67 to 76. The sensitization can also be performed by using any of sulfur, selenium, tellurium, gold, platinum, palladium, and iridium, or by using a combination of a plurality of these sensitizers at pAg 5 to 10, pH 5 to 8, and a temperature of 30xc2x0 C. to 80xc2x0 C., as described in Research Disclosure, Vol. 120, April, 1974, 12008, Research Disclosure, Vol. 34, June, 1975, 13452, U.S. Pat. Nos. 2,642,361, 3,297,446, 3,772,031, 3,857,711, 3,901,714, 4,266,018, and 3,904,415, and British Patent 1,315,755.
In the noble metal sensitization, salts of noble metals, such as gold, platinum, palladium, and iridium, can be used. In particular, gold sensitization, palladium sensitization, or a combination of the both is preferred. In the gold sensitization, it is possible to use known compounds, such as chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, and gold selenide, or mesoionic gold compounds described in U.S. Pat. No. 5,220,030 and azole gold compounds described in U.S. Pat. No. 5,049,484 and so on. A palladium compound means a divalent or tetravalent salt of palladium. A preferable palladium compound is represented by R2PdX6 or R2PdX4 wherein R represents a hydrogen atom, an alkali metal atom, or an ammonium group and X represents a halogen atom, e.g., a chlorine, bromine, or iodine atom.
More specifically, the palladium compound is preferably K2PdCl4, (NH4)2PdCl6, Na2PdCl4, (NH4)2PdCl4, Li2PdCl4, Na2PdCl6, or K2PdBr4. It is preferable that the gold compound and the palladium compound be used in combination with thiocyanate or selenocyanate.
A preferable amount of a gold sensitizer used in the invention is 1xc3x9710xe2x88x923 to 1xc3x9710xe2x88x927 mol, and more preferably, 1xc3x9710xe2x88x924 to 5xc3x9710xe2x88x927 mol per mol of a silver halide. A preferable amount of a palladium compound is 1xc3x9710xe2x88x923 to 5xc3x9710xe2x88x927 mol per mol of a silver halide. A preferable amount of a thiocyan compound or a selenocyan compound is 5xc3x9710xe2x88x922 to 1xc3x9710xe2x88x926 mol per mol of a silver halide.
Examples of a sulfur sensitizer are hypo, a thiourea-based compound, a rhodanine-based compound, and sulfur-containing compounds described in U.S. Pat. Nos. 3,857,711, 4,266,018, and 4,054,457. The chemical sensitization can also be performed in the presence of a so-called chemical sensitization aid. Examples of a useful chemical sensitization aid are compounds, such as azaindene, azapyridazine, and azapyrimidine, which are known as compounds capable of suppressing fog and increasing sensitivity in the process of chemical sensitization. Examples of the chemical sensitization aid and the modifier are described in U.S. Pat. Nos. 2,131,038, 3,411,914, and 3,554,757, JP-A-58-126526, and G. F. Duffin, Photographic Emulsion Chemistry, pages 138 to 143.
A preferable amount of a sulfur sensitizer used in the invention is 1xc3x9710xe2x88x924 to 1xc3x9710xe2x88x927 mol, and more preferably, 1xc3x9710xe2x88x925 to 5xc3x9710xe2x88x927 mol per mol of a silver halide.
As a preferable,sensitizing method for the emulsion of the invention, selenium sensitization can be mentioned. As a selenium sensitize used in the invention, selenium compounds disclosed in hitherto published patents can be used as the selenium sensitizer in the present invention. In the use of labile selenium compound and/or nonlabile selenium compound, generally, it is added to an emulsion and the emulsion is agitated at high temperature, preferably 40xc2x0 C. or above, for a given period of time. Compounds described in, for example, Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 44-15748, JP-B-43-13489, JP-A""s-4-25832 and 4-109240 are preferably used as the unlabile selenium compound.
Specific examples of the labile selenium sensitizers include isoselenocyanates (for example, aliphatic isoselenocyanates such as allyl isoselenocyanate), selenoureas, selenoketones, selenoamides, selenocarboxylic acids (for example, 2-selenopropionic acid and 2-selenobutyric acid), selenoesters, diacyl selenides (for example, bis(3-chloro-2,6-dimethoxybenzoyl) selenide), selenophosphates, phosphine selenides and colloidal metal selenium.
The labile selenium compounds, although preferred types thereof are as mentioned above, are not limited thereto. It is generally understood by persons of ordinary skill in the art to which the invention pertains that the structure of the labile selenium compound as a photographic emulsion sensitizer is not so important as long as the selenium is labile and that the labile selenium compound plays no other role than having its selenium carried by organic portions of selenium sensitizer molecules and causing it to present in labile form in the emulsion. In the present invention, the labile selenium compounds of this broad concept can be used advantageously.
Compounds described in JP-B""s-46-4553, 52-34492 and 52-34491 can be used as the nonlabile selenium compound used in the present invention. Examples of the nonlabile selenium compounds include selenious acid, potassium selenocyanate, selenazoles, quaternary selenazole salts, diaryl selenides, diaryl diselenides, dialkyl selenides, dialkyl diselenides, 2-selenazolidinedione, 2-selenoxazolidinethione and derivatives thereof.
These selenium sensitizers are dissolved in water or in a single solvent or a mixture of organic solvents selected from methanol and ethanol and added at the time of chemical sensitization. Preferably, the addition is performed prior to the initiation of chemical sensitization. The use of the above selenium sensitizers is not limited to a single kind, but the combined use of two or more kinds may be acceptable. The combined use of a labile selenium compound and an unlabile selenium compound is preferred.
The addition amount of the selenium sensitizer for use in the invention, although varied depending on the activity of employed selenium sensitizer, the type and size of silver halide, the ripening temperature and time, etc., is preferably in the range of 1xc3x9710xe2x88x928 or more. More preferably, the amount is 1xc3x9710xe2x88x927 mol or more and 5xc3x9710xe2x88x925 mol or less per mol of silver halide. The temperature of chemical ripening in the use of a selenium sensitizer is preferably 40xc2x0 C. or more and 80xc2x0 C. or less. The pAg and pH are arbitrary. For example, with respect to pH, the effect of the present invention can be exerted even if it widely ranges from 4 to 9.
Selenium sensitization is preferably used in combination with sulfur sensitization or noble metal sensitization or both of them. Further, in the present invention, a thiocyanic acid salt is preferably added in the silver halide emulsion at the chemical sensitization. As the thiocyanate, potassium thiocyanate, sodium thiocyanate, ammonium thiocyanate, and the like are used. It is usually added by being dissolved in an aqueous solution or a water-soluble solvent. The addition amount per mol of silver halide is 1xc3x9710xe2x88x925 mol to 1xc3x9710xe2x88x922 mol, and more preferably 5xc3x9710xe2x88x925 mol to 5xc3x9710xe2x88x923 mol.
It is preferred that in the silver halide emulsion of the present invention, an appropriate amount of calcium ion and/or a magnesium ion be contained. Thereby, the grain shape is made better, the quality of an image is improved, and the preservation property is made better. The range of the appropriate amount is 400 to 2500 ppm for calcium and/or 50 to 2500 ppm for magnesium, and calcium is more preferably 500 to 2000 ppm and magnesium is 200 to 2000 ppm. Herein, 400 to 2500 ppm for calcium and/or 50 to 2500 ppm for magnesium means that at least one of calcium and magnesium is a concentration within the range prescribed. When the content of calcium or magnesium is higher than these values, it is not preferable that inorganic salts which calcium salt, magnesium salt, a gelatin or the like has preliminarily retained precipitate and become the cause of trouble at the manufacture of the photographic material. Herein, the content of calcium or magnesium is represented by weight converted to calcium atom or magnesium atom for all of the compounds containing calcium or magnesium such as a calcium ion, a magnesium ion, a calcium salt, a magnesium salt and the like, and represented by concentration based on the unit weight of the emulsion.
The adjustment of the calcium content in the silver halide tabular emulsion of the invention is preferably carried out adding the calcium salt at the chemical sensitization. The gelatin generally used at manufacturing an emulsion contains already calcium by 100 to 4000 ppm as a solid gelatin, and calcium may be adjusted by adding a calcium salt to the gelatin to be increased. Further, if necessary, after carrying out the desalting (removal of calcium) from the gelatin according to a known method such as a washing method with water or an ion exchange method or the like, the content can be also adjusted by a calcium salt. As the calcium salt, calcium nitrate and calcium chloride are preferable, and calcium nitrate is most preferable. Similarly, the adjustment of the magnesium content can be carried out adding a magnesium salt. As the magnesium salt, magnesium nitrate, magnesium sulfate and magnesium chloride are preferable, and magnesium nitrate is most preferable. As the quantitative determination method of calcium or magnesium, it can be determined by ICP emission spectral analysis method. Calcium and magnesium may be used alone and a mixture of both may be used. It is more preferable to contain calcium. The addition of calcium or magnesium can be carried out at the arbitrary period of the manufacturing steps of the silver halide emulsion, but is preferably from after the grain formation to just after completion of the spectral sensitization and the chemical sensitization, and more preferably after addition of a sensitizing dye. Further, it is preferable in particular to add after addition of a sensitizing dye and before carrying out the chemical sensitization.
As a particularly effective compound for reducing the fog of the silver halide emulsion and suppressing the increase of the fog during preservation, a mercaptotetrazol compound having a water-soluble group described in JP-A-4-16838 is mentioned. Further, in the JP-A above, it is disclosed that the preservation property is enhanced by using the mercaptotetrazol compound and a mercaptothiadiazol compound in combination.
The surface or an arbitrary position from the surface of the emulsion used in the present invention may be chemically sensitized, but it is preferable to chemically sensitize the surface. When the inner part is chemically sensitized, a method described in JP-A-63-264740 can be referred.
Photographic emulsions used in the present invention can contain various compounds in order to prevent fog during the preparing process, storage, or photographic processing of a sensitized material, or to stabilize photographic properties. That is, it is possible to add many compounds known as antifoggants or stabilizers, e.g., thiazoles such as benzothiazolium salt; nitroimidazoles; nitrobenzimidazoles; chlorobenzimidazoles; bromobenzimidazoles; mercaptothiazoles; mercaptobenzothiazoles; mercaptobenzimidazoles; mercaptothiadiazoles; aminotriazoles; benzotriazoles; nitrobenzotriazoles; and mercaptotetrazoles (particularly 1-phenyl-5-mercaptotetrazole); mercaptopyrimidines; mercaptotriazines; a thioketo compound such as oxazolinethione; azaindenes such as triazaindenes, tetrazaindenes (particularly 4-hydroxy-substituted(1,3,3a,7)tetrazaindenes), and pentazaindenes. For example, compounds described in U.S. Pat. Nos. 3,954,474 and 3,982,947 and JP-B-52-28660 can be used. One preferred compound is described in JP-A-63-212932. Antifoggants and stabilizers can be added at any of several different timings, such as before, during, and after grain formation, during washing with water, during dispersion after the washing, before, during, and after chemical sensitization, and before coating, in accordance with the intended application. The antifoggants and stabilizers can be added during preparation of an emulsion to achieve their original fog preventing effect and stabilizing effect. In addition, the antifoggants and stabilizers can be used for various purposes of, e.g., controlling the crystal habit of grains, decreasing the grain size, decreasing the solubility of grains, controlling chemical sensitization, and controlling the arrangement of dyes.
The photographic emulsion for use in the present invention is preferably subjected to a spectral sensitization with a methine dye or the like to thereby exert the effects of the invention. Examples of employed dyes include cyanine dyes, merocyanine dyes, composite cyanine dyes, composite merocyanine dyes, holopolar cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly useful dyes are those belonging to cyanine dyes, merocyanine dyes and composite merocyanine dyes. These dyes may contain any of nuclei commonly used in cyanine dyes as basic heterocyclic nuclei. Examples of such nuclei include a pyrroline nucleus, an oxazoline nucleus, a thiazoline nucleus, a pyrrole nucleus, an oxazole nucleus, a thiazole nucleus, a selenazole nucleus, an imidazole nucleus, a tetrazole nucleus and a pyridine nucleus; nuclei comprising these nuclei fused with alicyclic hydrocarbon rings; and nuclei comprising these nuclei fused with aromatic hydrocarbon rings, such as an indolenine nucleus, a benzindolenine nucleus, an indole nucleus, a benzoxazole nucleus, a naphthoxazole nucleus, a benzothiazole nucleus, a naphthothiazole nucleus, a benzoselenazole nucleus, a benzimidazole nucleus and a quinoline nucleus. These nuclei may have substituents on carbon atoms thereof.
The merocyanine dye or composite merocyanine dye may have a 5 or 6-membered heterocyclic nucleus such as a pyrazolin-5-one nucleus, a thiohydantoin nucleus, a 2-thioxazolidine-2,4-dione nucleus, a thiazolidine-2,4-dione nucleus, a rhodanine nucleus or a thiobarbituric acid nucleus as a nucleus having a ketomethylene structure.
These spectral sensitizing dyes may be used either individually or in combination. The spectral sensitizing dyes are often used in combination for the purpose of attaining supersensitization. Representative examples thereof are described in U.S. Pat. Nos. 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,703,377, 3,769,301, 3,814,609, and 3,837,862, 4,026,707, GB Nos. 1,344,281 and 1,507,803, JP-B""s-43-4936 and 53-12375, and JP-A""s-52-110618 and 52-109925.
The emulsion used in the present invention may contain a dye which itself exerts no spectral sensitizing effect or a substance which absorbs substantially none of visible radiation and exhibits supersensitization, together with the above spectral sensitizing dye.
The addition timing of the spectral sensitizing dye to the emulsion may be performed at any stage of the process for preparing the emulsion which is known as being useful. Although the doping is most usually conducted at a stage between the completion of the chemical sensitization and the coating, the spectral sensitizing dye can be added simultaneously with the chemical sensitizer to thereby simultaneously effect the spectral sensitization and the chemical sensitization as described in U.S. Pat. Nos. 3,628,969 and 4,225,666. Alternatively, the spectral sensitization can be conducted prior to the chemical sensitization and, also, the spectral sensitizing dye can be added prior to the completion of silver halide grain precipitation to thereby initiate the spectral sensitization as described in JP-A-58-113928. Further, the above sensitizing dye can be divided prior to addition, that is, part of the sensitizing dye can be added prior to the chemical sensitization with the rest of the sensitizing dye added after the chemical sensitization as taught in U.S. Pat. No. 4,225,666. Still further, the spectral sensitizing dye can be added at any stage during the formation of silver halide grains according to the method disclosed in U.S. Pat. No. 4,183,756 and other methods.
The addition thereof may be set from 4xc3x9710xe2x88x926 to 8xc3x9710xe2x88x923 mol per mol of silver halide.
The silver halide grain other than the tabular grain used in the photographic material of the present invention will be described below.
The preferable silver halide contained in the photographic emulsion layer of the photographic material of the present invention is silver iodobromide, silver iodochloride or silver iodochlorobromide containing about 30 mole or less of silver iodide. Silver iodobromide or silver iodochlorobromide containing about 1 mole to about 10 moll of silver iodide is preferable in particular.
The silver halide grains in the photographic emulsion may be those having a regular crystal such as cubic, octahedral and tetradecahedral; those having a regular crystal shape such as sphere and tabular; those having a crystal defect such as twin plane or the like, or a complex shape thereof.
The grain may be a fine grain having a grain seize of about 0.2 xcexcm or less, and may be a large size grain having a projected area diameter up to about 10 xcexcm. The emulsion containing the grains may be a polydisperse emulsion or a monodisperse emulsion.
The silver halide photographic emulsion which can be used in the present invention can be prepared by, for example, xe2x80x9cResearch Disclosure (RD) No. 17643 (December in 1978), page 22 to 23xe2x80x9d, xe2x80x9cI. Emulsion Preparation and typesxe2x80x9d, xe2x80x9cibid., No. 18716 (November in 1979), page 648xe2x80x9d, xe2x80x9cibid., No. 307105 (November in 1989), page 863 to 865xe2x80x9d, xe2x80x9cChemie et Phisique Photographiquexe2x80x9d authored by P. Glafkides and published by Paul Montel Co., Ltd. (1967), xe2x80x9cPhotographic Emulsion Chemistryxe2x80x9d authored by G. F. Duffin and published by Forcal Press Co., Ltd. (1966), and xe2x80x9cMaking and Coating Photographic Emulsionxe2x80x9d authored by V. L. Zelikman et al and published by Forcal Press Co., Ltd.
Monodisperse emulsions described in U.S. Pat. Nos. 3,574,628 and 3,655,394, and GB 1,413,748 are preferable.
The crystal structure may be a uniform one, a structure consisting of a halogen composition in which inner part is different from outer part, and a laminar structure. Further, silver halide having a different composition may be joined by epitaxial junction, and may be joined with a compound such as Rodin silver, lead oxide or the like other than silver halide. Further, a mixture of grains having various crystal shapes may be used.
The above-mentioned emulsion may be any one of a surface latent image type in which a latent image is mainly formed on a surface, an internal latent image type in which a latent image is formed in the inside of grains, and a type having latent images both on a surface and in the inside, but requires a negative emulsion. Among the internal latent image types, it may be a core/shell type internal latent image type emulsion described in JP-A-63-264740. The preparation method of the core/shell internal latent image type emulsion is described in JP-A-59-133542. The thickness of the shell of the emulsion differs according to development treatment and the like, but is preferably 3 to 40 nm and preferably 5 to 20 nm in particular.
It is also possible to preferably use surface-fogged silver halide grains described in U.S. Pat. No. 4,082,553, internally fogged silver halide grains described in U.S. Pat. No. 4,626,498 and JP-A-59-214852, and colloidal silver, in lightsensitive silver halide emulsion layers and/or essentially non-lightsensitive hydrophillic colloid layers. The internally fogged or surface-fogged silver halide grains means a silver halide grain which can be developed uniformly (non-imagewise) regardless of whether the location is a non-exposed or an exposed portion of the photosensitive material. A method of preparing the internally fogged or surface-fogged silver halide grain is described in U.S. Pat. No. 4,626,498 and JP-A-59-214852.
A silver halide which forms the core of an internally fogged core/shell type silver halide grain can have the same halogen composition or a different halogen composition. As the silver halide composition of the internally fogged or surface-fogged silver halide grains, any of silver chloride, silver chlorobromide, silver iodobromide and silver chloroiodobromide can be used. Although the grain size of these fogged silver halide grains is not particularly limited, the equivalent sphere diameter thereof is 0.01 to 0.75 xcexcm, and especially preferably 0.05 to 0.6 xcexcm. Further, the grain shape is not specifically limited, and can be a regular grain and a polydisperse emulsion. However, it is preferably a monodisperse, i.e., at least 95% in weight or number of silver halide grains thereof have grain sizes falling within the range of xc2x140% of the average equivalent sphere diameter).
In the photographic material of the present invention, 2 or more of emulsions having at least one of different properties of the grain size, grain size distribution, halogen composition, grain shape and sensitivity of the lightsensitive silver halide emulsion can be used in the same layer by mixing.
In the preparation method of the photographic material of the invention, photographically useful substances are usually added to a photographic coating solution, i.e., a hydrophilic colloidal solution.
In silver halide photosensitive emulsion of the invention and the silver halide photographic material in which the emulsion is used, it is generally possible to use various techniques and inorganic and organic materials described in Research Disclosure Nos. 308119 (1989), 37038 (1995), and 40145 (1997).
In addition, techniques and inorganic and organic materials usable in color photosensitive materials of the invention can be applied are described in portions of EP436,938A2 and patents cited below.
When the photographic material of the invention is a color reversal material, image-forming method is provided thereto, in which the material is processed with an alkali developing solution containing a developer after it comes through an image-wise exposure and then black-and white development. After the color development, the color photographic material is processed with a processing solution having a bleaching ability in which a bleaching agent is contained.